The invention relates to a valve train of an internal combustion engine with a four-cylinder in-line arrangement and variable-stroke actuation of the gas exchange valves. The valve train comprises a first camshaft having a carrier shaft and precisely two first cam pieces, which are arranged for conjoint rotation thereon and so as to be movable between at least two axial positions and which each actuate the intake or exhaust valves of two adjacent engine cylinders by at least two first groups of adjacent cams having different lobes.
A sliding cam valve train of this kind, in which the gas exchange valves of two adjacent engine cylinders are actuated by a common cam piece, is known from DE 10 2005 006 489 A1 and DE 10 2009 016 902 A1. A prerequisite for the reduction achieved here in the complexity of the camshaft is the adequate size of the common base circle angle of all the cams of a cam piece since only this angular range is available for the shifting thereof in operation. Consequently, in-line four-cylinder engines (R4) having two overhead camshafts (DOHC) and the standard ignition sequence 1-3-4-2, in particular, are suitable for this purpose.
As part of the continued tightening of the emission regulations, there is now also an R4 engine with a sliding cam valve train and cylinder shutdown in production—see Motortechnische Zeitschrift MTZ March 2012: “Der 1,4-L-TSI-Ottomotor mit Zylinderabschaltung” (“The 1.4-l TSI spark-ignition engine with cylinder shutdown”).